EP2235253B1 - Method for treating cellulose moldings - Google Patents

Abstract

The present invention relates to a method for treating a cellulose molding, which is characterized in that the molding is brought in contact with an alkaline dispersion, which comprises undissolved chitosan particles. The chitosan particles are preferably present in the dispersion in a particle size from 0.1 to 1500 μm, preferably 1 to 800 μm.

Description

The invention relates to a process for the treatment of a cellulosic molding.

In particular, the invention relates to a method for modifying the properties of cellulosic moldings by means of chitosan.

Chitin and chitosan are natural, biodegradable, non-toxic, non-allergenic, bioactive and biocompatible polymers and similar in their structure to cellulose. Chitin is derived from crustacean casing, a waste product of the crab and shrimp industry. The global interest in the uses of chitin, as it is next to cellulose as the second largest resource for natural polysaccharides, has increased enormously in recent years.

Chitosan is composed of poly (1,4) -2-amino-2-deoxy-beta-D-glucose and is obtained by deacetylation of chitin (poly (1,4) -2-acetamide-2-deoxy-beta-D Glucose). For reasons of solubility - chitin is insoluble in water, organic solvents, dilute acids and alkalis - chitosan, which is soluble in dilute acids, aqueous methanol and glycerine, is of far greater importance.

Fields of application for chitin and chitosan are in biotechnology for the immobilization of cells and enzymes, in medicine for wound treatment, in the food sector as food additive and preservative, in agriculture for seed conservation, in sewage systems as flocculants and chelating agents with heavy metals.

However, for most applications, chitin / chitosan modification must be performed to improve solubility in aqueous systems.

• Herstellung von 100% Chitosanfasern bzw. Herstellung von "Man Made Fibres" mit Inkorporation von Chitosan
• Finishing und Coating von Textilfasern
• Prozesshilfsstoffe für die Textilindustrie

The use of chitosan in the textile industry is divided into three areas of application:

• Production of 100% chitosan fibers or production of "Man Made Fibers" with incorporation of chitosan
• Finishing and coating of textile fibers
• Processing auxiliaries for the textile industry

Chitosan fibers find their application in the medical field, for example as wound coverings and surgical suture threads due to the antibacterial properties and the growth inhibition on pathogenic germs. Chitin or chitosan can be degraded enzymatically or hydrolytically by the body's own enzymes and are therefore absorbable fibers. The effect of these natural polymers in wound healing consists in the gradual release of N-acetyl-glucosamine, the mucopolysaccharide organization of the collagen and the positive influence on tissue growth in the course of wound healing ( EP 0 077 098 . US 4309534 . JP81 / 112937 . JP84 / 116418 and many more).

The disadvantage of fibers made of 100% chitosan, however, is that they have a low dry strength (chitosan fibers from the company Innovative Technology Ltd., Winsford, England: titer 0.25 tex, fiber strength conditioned 9 cN / tex, fiber elongation conditioned 12.4% Chitosan fibers of the company Korea Chitosan Co. LTD: fiber strength conditioned 15 cN / tex, fiber elongation conditioned 26%), are extremely brittle and the wet strength is only 30% of the dry strength. Therefore either chitosan fibers are mixed with other man-made fibers or already used in the manufacturing process of e.g. Viscose fibers chitosan added to the spinning mass.

Commercially available are viscose fibers with incorporated chitin / chitosan (hereinafter: "chitosan-incorporated viscose fibers"), for example under the trade name Crabyon (Omikenshi Co.) and Chitopoly (Fuji Spinning Co.). These fibers are prepared, for example, by dispersing chitosan or acetylated chitosan in powder form having a particle size of less than 10 μm in an amount of from 0.5 to 2% by weight in water and adding the viscose spinning solution ( US 5,320,903 ). Then fibers are produced by the conventional viscose or polynosic process.

Other production processes for chitosan-incorporated viscose fibers are described in US Pat US-A 5,756,111 (elaborate pre-and post-dissolution processes at cryogenic temperature to obtain alkaline chitin-chitosan solutions for addition to the viscose solution), the US-A 5,622,666 (Addition of microcrystalline chitosan and a water- and / or alkali-soluble natural polymer, for example, sodium alginate, which can form ionic bonds to chitosan, as a dispersion to Viskosespinnlösung) and PCT / FI90 / 00292 respectively. FI 78127 (Addition of microcrystalline chitosan to the spinning mass) described.

The chitosan-incorporated viscose fibers have increased dye affinity, increased water retention, anti-fungicidal and odor-inhibiting properties, however also known for viscose fibers low wet strength. Since chitosan prevents the growth of bacteria harmful to the skin and eliminates allergic effects, eg chitopoly tissues are particularly suitable for dermatitis patients.

The disadvantage of all the methods described is that the fibers thus obtained contain the finest chitosan particles, since the chitosan is not soluble in the spinning mass.

The secondary agglomeration of chitosan in the dope or the inhomogeneous distribution leads to a deterioration of the spinning properties, the spinning of fibers with low titers is extremely difficult. For this reason, the amount of incorporated chitosan can not be increased because it immediately causes a loss of textile data or it already comes to numerous thread breaks during spinning. Furthermore, since chitosan is soluble in acids, chitosan losses occur in the spinning bath. For the incorporation of chitosan additional elaborate steps are necessary.

In order to ensure the effect of the chitosan in the final product, moreover, an amount of at least about 10% by weight of chitosan must be incorporated into the fibers, since only then is sufficient chitosan on the fiber surface. The chitosan incorporated in the fibers is inaccessible and therefore ineffective.

As a result, it has also been attempted to incorporate chitosan into solvent-spun cellulose fibers made by the amine oxide process (so-called "lyocell fibers"), in particular because of the high wet and dry strength of the lyocell fibers.

In the DE 195 44 097 For example, there is described a process for the preparation of moldings from polysaccharide mixtures by dissolving cellulose and a secondary polysaccharide in an organic, water-miscible polysaccharide solvent (preferably NMMO), which may also contain a secondary solvent.

Furthermore, in the KR-A 9614022 describe the preparation of chitin - cellulose fibers, called "chitulose", by dissolving chitin and cellulose in a solvent selected from dimethylimidazolines / LiCl, dichloroacetate / chlorohydrocarbon, dimethylacetamide / LiCl, N-methylpyrrolidone / LiCl and making yarns by the wet spinning process become. In the claims, NMMO is not mentioned.

In the EP-A 0 883 645 Among other things, the addition of chitosan is claimed to the solution as a modified compound to increase the suppleness of food casings. The Modifying compounds must be miscible with the cellulose / NMMO / water solution.

The KR-A-2002036398 describes the incorporation of elaborately prepared chitosan derivatives with quaternary ammonium groups in fibers.

In the DE-A 100 07 794 describes the preparation of polymer compositions comprising a biodegradable polymer and a material from marine plants and / or shells of marine animals and the production of moldings therefrom. Claimed is also the addition of material from sea plants, seafood in powder form, powder suspension or liquid form to the cellulose solution prepared by the Lyocellverfahren. Furthermore, the material can also be added after or during the comminution of the dry cellulose, and at any stage of the manufacturing process. Despite the addition of the additive, the fibers show the same textile mechanical properties as without additive. In the examples, only lyocell fibers are described which have incorporated brown algae powder, the brown algae meal, NMMO and pulp and stabilizer being mixed and heated to 94 ° C to produce the dope.

Furthermore, in the final report " Products of Polysaccharide Compounds "(Taeger, E., Kramer, H., Meister, F. Vorwerg, W. Radosta, S. TITK - Thuringian Institute for Textile and Plastics Research, 1997, p.1-47, Report No. FKZ 95 / NR 036 F ) that chitosan is dissolved in dilute organic or inorganic acids and then precipitated in aqueous NMMO solution. This gives a suspension of fine chitosan crystals in the cellulose solution, which is then spun. According to this document, the chitosan remains in the solution even after dissolving the cellulose as fine crystals. This leads to a microheterogeneous second phase system in the fiber. The strength of the fiber is low (at 10% chitosan fiber strength conditioned 19.4 cN / tex, fiber elongation conditioned 11.5%).

In the WO 04/007818 For example, it is proposed to incorporate a dope-soluble chitosonium polymer (a salt of chitosan with an inorganic or organic acid) into the lyocell fiber by addition to the dope or a precursor thereof.

As an alternative to incorporation, it is possible to equip textile fabrics with chitosan during production. Applying chitosan on already fibers produced or textile articles containing them is also referred to below as "impregnation". A fundamental problem with this is that the chitosan thus applied is not fixed and is washed out relatively quickly, as a result of which the positive effects are lost.

To work around this problem, is in the EP 1 243 688 proposed the use of chitosan nanoparticles for the production of fibers, yarns, knitted fabrics and textile fabrics. Nano-chitosans are understood to mean approximately spherical solids which have a mean diameter in the range from 10 to 300 nm and, due to the small particle diameter, are interposed between the fibrils. The production of nano-chitosans takes place by spray-drying, evaparation or relaxation of supercritical solutions.

In the WO 01/32751 describes a process for the preparation of nanoparticulate chitosan for cosmetic and pharmaceutical preparations having particle diameters of 10 to 1000 nm, in which the pH of an aqueous acidic solution of chitosan in the presence of a surface modifier is raised so far that it comes to precipitation of the chitosan. Furthermore, in the WO 91/00298 describes the preparation of microcrystalline chitosan dispersions and powders with particle diameters of 0.1 to 50 microns, in which one raises the pH of an aqueous acidic chitosan solution so far that it comes to the precipitation of the chitosan.

The WO 97/07266 describes the treatment of a lyocell fiber with a 0.5% acetic acid chitosan solution.

In the WO 2004/007818 In addition to the incorporation of a chitosonium polymer in lyocell fibers, the treatment of never-dried lyocell fibers with the solution or suspension of a chitosonium polymer is also described. It has been found that this method is only suitable for the treatment of never dried Lyocell fibers.

The term "never dried" indicates the state of a freshly spun fiber which has not yet undergone a drying step.

A treatment of fiber types other than Lyocell fibers never dried is with the method according to the WO 2004/007818 not possible.

The object of the present invention is to provide a process for the treatment of cellulosic moldings which does not have the aforementioned problems of incorporation of chitosan into fibers and which is suitable for various types of cellulose fibers, never dried. The chitosan is to be fixed in particular on the fiber surface of cellulose regenerated fibers (lyocell fibers, modal fibers, viscose fibers, polynosic fibers) preferably during the manufacturing process so that the chitosan is still present on the final product after a series of household washes ,

This object is achieved by a process according to claim 1 for the treatment of a cellulosic shaped body, which is characterized in that the shaped body is brought into contact with an alkaline dispersion which contains undissolved chitosan particles.

It has surprisingly been found that a sustainable application of chitosan to the surface of cellulosic moldings is possible when the moldings are brought into contact with an alkaline dispersion containing undissolved chitosan particles. The chitosan particles are present in the dispersion preferably in a particle size of from 0.1 to 1500 .mu.m, particularly preferably from 1 to 800 .mu.m. The pH of the dispersion is preferably more than 7, particularly preferably 9 to 11.

There is no consistent definition in the literature of the distinction between chitin and chitosan.

For the purposes of the present invention, the term chitin is intended to mean a β-1,4-linked polymer of 2-acetamido-2-deoxy-D-glucose having a degree of deacetylation of 0% Further, for the purposes of the present invention, the term "Chitosan" is an at least partially deacetylated β-1,4-linked polymer of 2-acetamido-2-deoxy-D-glucose.

Compared with the known methods for incorporating chitosan, the method according to the invention has the advantage that an incorporated chitosan is not accessible in the interior of the shaped body. Only chitosan on the surface of the molding can come in contact with the skin and thus develop its positive effect. Therefore, in order to achieve the same amount of chitosan as impregnated on the surface of a molded article, much higher amounts of chitosan must be used in the incorporation.

In particular, there is an advantage over the use of nano-chitosan due to the high production cost of nano-chitosan.

Opposite in the WO 2004/007818 described method in the inventive method has the advantage that the impregnation described there with an acidic solution of a chitosonium polymer in the treatment of never-dried viscose, modal or Polynosicfasern with subsequent steaming does not work. There are only very low Chitosanauflagen achieved, and the implementation of this method is not possible without modification of existing plants.

In addition, the inventive method is cheaper than that in the WO 2004/007818 described method, since preferably cheaper chitosan types can be used (see below).

According to a preferred embodiment of the method according to the invention, the content of the chitosan particles in the dispersion is 0.001 to 10% by weight, preferably 0.1 to 2% by weight.

It has been found that all commercially available chitosan types which are soluble in an acid (for example lactic acid) and, when precipitated with alkali, give dispersions with chitosan particles having a particle size of 0.1 to 1500 μm, are suitable for carrying out the process according to the invention. The solubility of a chitosan type in acids depends essentially on the degree of de-acetylation of the chitosan. If the de-acetylation is too low, the solubility will be worse.

In particular, relatively high molecular chitosan types (having a viscosity of 1% strength solution in 1% strength acetic acid at 20 ° -25 ° C. of 200 mPa.s or more, measured with Brookfield Viscosimeter at 30 rpm) are also suitable for carrying out the process according to the invention. Higher molecular weight chitosans are generally less expensive.

The shaped body treated according to the invention is preferably in the form of fibers. The fibers are lyocell fibers, modal fibers, polynosic fibers and / or viscose fibers.

The generic name "lyocell" has been awarded by BISFA (The International Bureau for the Standardization of Man Made Fibers) and stands for cellulose fibers made from solutions of cellulose in an organic solvent. Prefers are used as solvents tertiary amine oxides, in particular N-methyl-morpholine-N-oxide (NMMO). A process for the production of Lyocell fibers is eg in the US-A 4,246,221 described.

Viscose fibers are fibers obtained from an alkaline solution of cellulose xanthogenate (viscose) by precipitation and regeneration of the cellulose.

Modal fibers are cellulosic fibers that are characterized by high wet tensile strength and high wet modulus (the force needed to stretch a fiber when wet by 5%), as defined by BISFA.

The fibers are never in a dried form. The fibers may be present in particular in the form of a non-woven fabric, as occurs during the production process of lyocell, viscose, modal and Polynosicstapelfasern as an intermediate.

This variant has the advantage that the treatment can be implemented without the necessity of apparative changes in an existing plant for the production of lyocell, viscose, modal or polynosic fibers. Treatment of never-dried viscose, modal or polynosic fibers with chitosan has not previously been described.

The fibers may have a residual moisture of 50% to 500% before treatment.

After the treatment with the dispersion containing chitosan particles, the molding may be subjected to superheated steam treatment. As a result, an additional fixation of the chitosan on the surface of the molding can be achieved.

To prepare the chitosan dispersion, chitosan is preferably dissolved in an inorganic or organic acid (e.g., lactic acid), and then alkali is added to precipitate the chitosan. Most preferably, after complete dissolution of the chitosan with stirring of the chitosan solution, an aqueous alkali hydroxide solution, e.g. NaOH, added to increase the pH to> 7. The final pH is preferably 9 to 11.

The chitosan dispersion thus obtained may, for example, be used for continuous treatment with an initially moist, e.g. Pressing to a defined moisture of 50% to 500% adjusted cellulose Regeneratfaservlies be brought into contact. The nonwoven may e.g. be soaked by spraying. For this, e.g. without the need for a conversion of existing production facilities in plants for the production of viscose fibers and modal fibers the so-called bleaching field can be used.

After impregnation, the web can be pressed to a defined moisture content of 50% - 500% and the squeezed treatment liquor can be returned to the impregnation circuit.

Thereafter, the fleece is either treated with superheated steam and then washed neutral or washed neutral without steam treatment, scavenged and dried.

Another preferred variant of the method is that the dispersion is prepared in situ by metering an acidic solution of chitosan into an alkaline treatment liquid, for example an oiling bath, and the molding is treated simultaneously with the treatment liquid and the dispersion formed in situ .

If the acidic chitosan solution is metered, for example, into a fiber-conditioning bath which has a pH of> 7, the chitosan dispersion is generated in situ and the fiber is simultaneously impregnated with chitosan and then refined. Subsequently, the fiber can be dried without washing.

In a further preferred embodiment, the shaped body is subjected to a treatment with a crosslinking agent before or after drying.

Suitable crosslinking agents are for example in the WO 99/19555 described. Such crosslinking agents are applied to the fiber in an alkaline medium. If, in a typical procedure, the fiber is brought into contact with the crosslinking agent in an alkaline medium, if necessary by means of superheated steam fixes the crosslinking agent and then applying an acidic solution of chitosan to the fiber, also due to the alkalinity of the fiber surface in situ formation of an alkaline Chitosan dispersion.

In general, according to the invention, therefore, the alkaline chitosan dispersion can also be prepared in situ by applying an acidic chitosan solution to an alkaline or fiber surface alkaline due to alkaline pretreatment.

The present invention also relates to a shaped article obtainable by the method according to the invention.

The shaped body according to the invention can be present in particular in the form of fibers, preferably lyocell fibers, modal fibers, polynosic fibers and / or viscose fibers.

A characteristic of the moldings obtainable by the process according to the invention is that the surface of the mold has punctiform distributed chitosan particles. For moldings, for example, according to the method according to the WO 04/007818 In contrast, a film-like distribution of chitosan particles on the surface is detectable.

The present invention also relates to the use of a shaped article according to the invention as an antibacterial product, as an odor-inhibiting product, in nonwovens products and / or as filler fiber. Preferred fields of application of chitosan-containing cellulose regenerate fibers according to the invention comprise textiles worn close to the body, such as, for example, mildly antibacterial, odor-inhibiting, skin-friendly properties. Underwear or socks, textiles for people with sensitive skin (atopic dermatitis), bed linen and home textiles. As a filler fiber, the fiber of the invention can be used both alone and in blends with other fibers, such as e.g. Cotton, polyester fibers and unmodified cellulose fibers (e.g., lyocell fibers).

In the following the invention by examples and the drawings will be explained in more detail.

It shows FIG. 1 the distribution of the chitosan particles on the surface of a lyocell fiber produced according to the invention. FIG. 2 shows the distribution of chitosan on the surface of a lyocell fiber, which after the in WO 2004/007818 described method (application of an acidic solution of a chitosonium polymer) was prepared.

EXAMPLES Example 1 Impregnation with Chitosan Dispersion (0.4% by Weight Chitosan) Recipe for the chitosan solutions:

To prepare 500 ml of a 0.4% chitosan solution, 2 g of chitosan are made up to 497.6 g with distilled water, admixed with 2.4 g of lactic acid (81.2%), stirred until the chitosan is completely dissolved, and then with stirring adjusted to a pH of 11.0 with 5% NaOH solution. The result is an approximately 0.4% chitosan dispersion.

Procedure for fiber impregnation:

• Variante a) 10 mal mit Leitungswasser und 10 mal mit destilliertem Wasser ausgewaschen, getrocknet und kardiert
• Variante b) 5 min bei 100°C/100% relativer Feuchtigkeit gedämpft, ausgewaschen, getrocknet und die Probe kardiert

Never dried fibers are used with a liquor ratio of 1:10 5 min. long impregnated with the dispersion at room temperature and then pressed with 1 bar. After that will

• Variant a) Washed 10 times with tap water and 10 times with distilled water, dried and carded
• Variant b) Steamed at 100 ° C / 100% relative humidity for 5 min, washed, dried and the sample carded

Used fiber samples:

• 1.3 dtex lyocell fiber washed NMMO-free, never dried
• 1.3 dtex modal fiber not bleached, never dried
• 1.3 dtex viscose fiber not bleached, never dried

Used commercially available chitosan types:

Fa. Heppe Type 85/200 / A1 (which means a deacetylation degree of 85 and a viscosity of a 1% solution in 1% acetic acid of 200 mPa.s),
Chitosan particle size in the dispersion: 90% <675 μm
From Primex Type Chitoclear fg 95ULV ™ 2284, chitosan particle size in the dispersion: 90% <15 μm.

Measurement Methods:

The determination of the chitosan particle size in the dispersion takes place by means of laser diffraction (measuring device Fa. Sympatec / Helos Quixel, wet dispersing system).
The determination of the chitosan coating on the fiber is carried out by measuring the N content (LECO FP 328 nitrogen analyzer) by annealing the sample.
A FITC (fluorescein isothiocyanate) staining of the fibers followed by fluorescence microscopy of the fibers was performed to analyze the chitosan distribution on the fiber surface.

To check the permanence of the chitosan coating on the laboratory samples, a hot water treatment is carried out: boil the card sliver of the chitosan impregnated fibers at 80 to 90 ° C in the beaker (liquor ratio 1:20, after 20 min at 80 to 90 ° C water, after Reach the temperature again for 20 min.

The result of the experiments is listed in the following Table 1: Table 1 Chitosan Pad % Chitosan 85/200 / A1 % Chitosan TM2284 % Chitosan after hot water treatment 85/200 / A1 % Chitosan n. Hot water treatment TM2284 Lyocell variant a) 1.3 0.25 1.3 0.20 Lyocell variant b) 1.0 0.42 1.0 0.35 Modal variant a) 1.1 0.32 1.1 0.17 Modal variant b) 1.5 0.29 1.6 0.16 Viscose variant a) 1.2 0.31 1.1 0.23 Viscose variant b) 1.0 0.44 1.3 0.30

Example 2 Impregnation with Chitosan Dispersion (0.2% by Weight Chitosan)

To prepare 500 ml of a 0.2% chitosan solution, 1 g of chitosan are made up to 498.8 g with distilled water, 1.2 g of lactic acid (81.2%) are added, stirred until the chitosan is completely dissolved and then while stirring 5% with NaOH to a pH of 10.0. The result is an approximately 0.2% chitosan dispersion.

Procedure for fiber impregnation:

The procedure is as in Example 1 (variants a) and b)).

Used fiber samples:

1.3 dtex lyocell washed NMMO-free, never dried

Used commercially available chitosan type:

Fa. Heppe Type 85/400 / A1 (viscosity of a 1% solution in 1% acetic acid of 400 mPa.s), chitosan particle size in the suspension 90% <305 microns

Knit stockings were made from the fibers and the permanence of the chitosan overlay was tested under high temperature polyester dyeing conditions ("HAT permanence").

The result of the experiments is listed in the following Table 2: Table 2 Chitosan Pad % Chitosan 85/400 / A1 % Chitosan 85/400 / A1 after HAT % Chitosan TM2284 % Chitosan TM2284 after HAT Lyocell variant a) 0.71 0.57 0.30 0.28 Lyocell variant b) 0.93 0.89 0.31 0.30

Example 3 - Impregnation in the bath

To prepare 500 ml of a 0.2% chitosan solution, 1 g of chitosan are made up to 498.8 g with distilled water, 1.2 g of lactic acid (81.2%) are added, stirred until the chitosan is completely dissolved and then while stirring 5% with NaOH to a pH of 10.0. The result is an approximately 0.2% chitosan dispersion.

Used fiber samples:

• 1.3 dtex lyocell washed NMMO-free, never dried, with 100% humidity
• 1.3 dtex modal not bleached, never dried, with 100% moisture

Used commercially available chitosan types:

Fa. Heppe Type 85/400 / A1, chitosan particle size in the suspension: 90% <305 μm
Fa. Primex Type Chitoclear fg 95 ULV ™ 2284, Chitosan particle size in suspension: 90% <15 μm.

An oiling bath with pH 8 and 15 g / l of active substance was produced at 60 ° C. The 0.2% chitosan dispersion was added to chitosan dispersion in a ratio of 1: 1 bath to give a chitosan concentration in the bath of 0.1%.

Procedure Fiber Impregnation:

Never dried fibers are used with a liquor ratio of 1: 10 5 min. long impregnated at 60 ° C and then pressed with 3 bar and dried.

Knit stockings were made from the fibers and the permanence of the chitosan overlay was tested under high temperature polyester dyeing conditions ("HAT permanence").

The result of the experiments is listed in the following Table 3: Table 3 Chitosan Pad % Chitosan 85/400 / A1 % Chitosan 85/400 / A1 after HAT % Chitosan TM2284 % Chitosan TM2284 after HAT lyocell 0.52 0.45 0.61 0.36 Modal 0.49 0.42 0.64 0.30

Example 4 - Preparation of a 6.7 dtex 60 mm cellulose regenerated fiber with chitosan and silicone Recipe for the chitosan solutions:

To prepare 500 ml of a 0.6% chitosan solution, 3 g of chitosan are made up to 496.4 g with distilled water, 3.6 g of lactic acid (81.2%), stirred until the chitosan is completely dissolved and then with stirring 5% NaOH to a pH of 11.0. The result is an approximately 0.6% chitosan dispersion.

Procedure Fiber Impregnation:

Never dried fibers with a liquor ratio of 1:10 5 min. long impregnated at room temperature and then pressed with 1 bar. The mixture is then washed 10 times with distilled water and then the fiber at room temperature in a liquor ratio of 1: 12 5 min. long in a silicone bath with an active content of 13 g / l, pressed with 1 bar, dried and carded.

Used commercially available chitosan types:

Fa. Primex Chitoclear fg 95 ULV ™ 2284, Chitosan particle size in suspension: 90% <15 μm

Used fiber samples:

• 6.7dtex lyocell washed NMMO-free, never dried
• 6,7dtex modal trilobal (according to WO 2006/060835 ), not bleached, never dried

The fibers were subjected to a household wash in a washing machine (gentle cycle at 60 ° C, commercially available liquid detergent, dosage according to the manufacturer, fibers in laundry bags, wash after household washing once again by hand, dry). There were three washes done.

The result of the experiments is listed in the following Table 4: Table 4 Chitosan Pad % Chitosan TM2284 % Chitosan after household washing 6.7 dtex Lyocell 0.45 0.33 6.7 dtex modal trilobal 0.49 0.34

Example 4 - Production Trials - Preparation of a 1.7dtex 38 mm lyocell fiber with chitosan

According to the in the WO 93/19230 in the continuous production process, fibers of the genus Lyocell were produced with 1.7dtex 38 mm and never dried according to the invention with a dispersion of alkaline precipitated chitosan, type TM 2284 (0.2% by weight) in a liquor ratio of 1:20 to a target coverage of 0 , 6% by weight of chitosan impregnated, steamed, washed out, washed and dried. From the fibers thus produced with an achieved chitosan coverage of 0.5% by weight, yarns Nm 50 were spun and processed into a textile fabric (single jersey knit), which had 0.4% by weight chitosan coating. After 10 household washes, the chitosan content was still 0.3% by weight.

FIG. 1 shows a confocal microscopy image of a prepared according to Example 4 and fluorescein isothyocyanate-dyed fiber. The punctiform distribution of chitosan (bright spots) is clearly visible.

FIG. 2 shows the distribution of chitosan on the surface of a lyocell fiber, which after the in WO 2004/007818 described method (application of an acidic solution of a chitosonium polymer) was prepared. The chitosan (bright areas) is distributed like a film on the surface.

Claims (14)

1. A process for the treatment of a cellulosic moulded body in the form of fibres, characterized in that the moulded body is contacted with an alkaline dispersion containing undissolved chitosan particles, that the fibres are lyocell fibres, modal fibres, polynosic fibres and/or viscose fibres and that the fibres are never-dried.
2. A process according to claim 1, characterized in that the chitosan particles are present in the dispersion in a particle size of from 0.1 to 1500 µm, preferably from 1 to 800 µm.
3. A process according to claim 1 or 2, characterized in that the pH-value of the alkaline dispersion exceeds 7, preferably ranging from 9 to 11.
4. A process according to any of the preceding claims, characterized in that the content of chitosan particles in the dispersion ranges from 0.001 to 10% by weight, preferably from 0.1 to 2% by weight.
5. A process according to any of the preceding claims, characterized in that the chitosan used for the production of the dispersion has a viscosity of 200 mPa.s or more in a 1% solution in 1% acetic acid at 20 - 25°C.
6. A process according to any of the preceding claims, characterized in that the fibres are present in the form of a fibre fleece.
7. A process according any of the preceding claims, characterized in that the fibres have a residual moisture of from 50% to 500% prior to the treatment.
8. A process according to any of the preceding claims, characterized in that the moulded body is subjected to a treatment with superheated steam after the treatment with the dispersion.
9. A process according to any of the preceding claims, characterized in that, for the production of the dispersion, chitosan is dissolved in an inorganic or organic acid, and subsequently alkali is added for the precipitation of the chitosan.
10. A process according to claim 9, characterized in that the dispersion is produced in situ by metering an acidic chitosan solution into an alkaline treatment liquid, preferably a finishing bath, and the moulded body is treated at the same time with the treatment liquid and the dispersion formed in situ.
11. A process according to claim 9, characterized in that the dispersion is produced in situ by applying an acidic chitosan solution onto a fibre surface which is alkaline as a result of an alkaline pretreatment.
12. A moulded body obtainable by a process according to any of claims 1 to 11.
13. A moulded body according to claim 12, characterized in that the surface of the moulded body exhibits chitosan particles distributed in a spot-like manner.
14. The use of a moulded body according to any of claims 12 or 13 as an antibacterial product, as an odour-reducing product, in nonwoven products and/or as a filling fibre.

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